Applicant originated the category of collapsible light control grids in his U.S. Pat. No. 5,556,186. Such light control grids for photographer's soft boxes are generally made of intersecting and interlocking strips of fabric, formed in two sets, strips of one set intersecting the strips of the other set. The strips of intersecting sets are slotted in a complimentary manner and inserted one through the other to define a plurality of light channels. Alternatively, the control grid may be created by sewing the adjoining corners of fabric light channels. Applicant is also the inventor of light control grid for close up work in U.S. Pat. No. 8,579,447, and light control grids for architectural applications in U.S. Pat. Nos. 7,198,388 and D537,957.
A standard prior art photographic setup using the light control grid is shown in FIG. 1. To create soft light conditions, a light source (20), “soft box,” or lightbox with a square or polygonal aperture (30) forming a reflective enclosure around the lamp is used. A light control grid (26) is mounted within the square aperture to cast light upon a desired subject (22) and scene (28), such that a photo may be taken with the camera (24).
Since the light control grid (26) is made of flexible fabric strips and must be inserted into flexible fabric lightbox aperture (30), it can be difficult to attach to the soft box (20). Further, once the control grid (26) is installed within the aperture (30), the fabric strips of the light grid often deflect or sag, which is especially an issue with larger soft boxes.
Others attempted to solve this issue by creating a flexible frame made from two L-shaped frame members made from tape springs that together enclose a rectangular perimeter for supporting the flexible grid within. The tape springs are inserted into long sleeves and bent to form two of the four corners of the control grid. The other two corners are formed by sewing together the free ends of the L-shaped frame members, so that two diagonally arranged corners are sewn and the other two diagonally arranged corners are formed by bending the tape spring. The tape springs are metal strips biased to a straight configuration due to being bent about the longitudinal axis, but may be bent or rolled along its length.
The L-shaped tape springs are at times difficult to open to a rectangular configuration, as the tape spring frame may bend at any point, as the two tape spring corners may be slightly difficult to discover. Additionally, the grid, while being supported at the edges, remains unsupported across the center, which may sag, especially if a large grid.
What is needed is a light control grid with a frame that can be collapsed and folded in the assembled state, and expanded to a rectangular or polygonal shape where the corners are easily discoverable, such that the light control grid readily conforms to the rectangular aperture of a soft box. Also finding a way to better support the center portion of large grids would be advantageous.